Factorio Forums

Lengthy title, but a picture is worth a thousand words:


Here you can see I connected the lubricant to one of the water outputs of Space Exploration's Decontamination Facility and as you can see the pipe connected to the other fluid output says that there is lube in the system even though there is no possible way for the lube to move to that pipe.

Then don't connect a the wrong fluid to the wrong output you might say. But the same problem applies when placing buildings against each other:


Here two Mechanical Facilities touch each other with a different fluid output and even though those two fluids can't move in any pipe, it still messes with the other two fluid outputs.

The main problem with this in some cases can lead to the "Can't mix fluids" error message even though you aren't mixing fluids, the game just thinks you are.

Obviously this only happens in modded games since no vanilla building has multiple identical fluid outputs as far as I'm aware.

Mods used: Space Exploration mod pack.

The different connections are part of the same fluid system. NaB.

Loewchen wrote: ↑

Tue Mar 29, 2022 9:40 pm

The different connections are part of the same fluid system. NaB.

It's a very non intuitive behavior because fluids can't flow between the two input ports. So to the player, it doesn't seem like they are connected at all, yet the fluid display shows they are.

robot256 wrote: ↑

Tue Mar 29, 2022 10:02 pm

It's a very non intuitive behavior because fluids can't flow between the two input ports. So to the player, it doesn't seem like they are connected at all, yet the fluid display shows they are.

As long as both inputs can fill the same input fluid box, they have to be the same fluid system as otherwise in the multithreaded fluids update (where a unit of work is a fluid system) there would be a possibility for a race condition that could result in a desync. Also it is possible to abuse one of the mechanics to take fluid out of the other port by using a pump directly next to the input pipe: pump will be able to take the fluid content out of a machine.

Huh never knew you could pump fluids out of an input. Only knew that deconstructing or changing the recipe of the machine will allow fluid to flow backwards as it tries to find someplace to put them.

Silari wrote: ↑

Wed Mar 30, 2022 6:02 am

Huh never knew you could pump fluids out of an input. Only knew that deconstructing or changing the recipe of the machine will allow fluid to flow backwards as it tries to find someplace to put them.

Abusing pump to take fluid out is not that useful in general and its minor enough noone wants to fix this as it would be literally more checks for the pump to do every tick (get the opposite pipe connection data and check if its output or inputoutput). Doable but minor. Also a pair of pumps can steal the fluid content from each other if one of them started with some fluid.